I think there's been a misunderstanding of "It was only after the advent of digital photography, however, that it became possible to create sharp colour prints." I believe the writer was referring specifically to the photographs in the set, each of which were made on three separate glass plates (not unlike, I would guess, the three-strip Technicolor motion picture process) and it was only with the advent of digital scanners and layering that the previously separate monochrome glass plates could be combined to make what we would think of as a conventional color photograph.